First, there was The Girl with the Dragon Tattoo. Then, she Played With Fire and Kicked the Hornet’s Nest. Now, more than 10 years since Lisbeth Salander’s creator Stieg Larsson died, his British publisher is preparing for the release of the fourth novel in the bestselling Millennium series, which it has announced will be called The Girl in the Spider’s Web.

Larsson redux ... The cover for The Girl in the Spider’s Web. Photograph: PR

Penned by Swedish writer David Lagercrantz with the blessing of Larsson’s estate – though not his long-term partner – the novel, based on Larsson’s universe and characters, will be published worldwide on 27 August. Amid Harry Potter-style levels of security – Lagercrantz wrote the work on a computer with no internet connection, and delivered the Swedish manuscript to his publishers by hand – UK publisher MacLehose Press has unveiled only the cover, which shows Salander herself, complete with dragon tattoo and a suitably punk pair of trousers.

Called Det som inte dödar oss in the original Swedish, or What Doesn’t Kill You, it is now in the process of being translated into 38 different languages, with George Goulding working on the English version.

“The Swedish original publishers Norstedts have put everyone on notice that no particle of this book can be shared with anybody,” said UK publisher Christopher MacLehose. “There’ll be no review copies in any language before it’s launched on 27 August … Nobody will be in a position to beat the ring of steel around this book.”

It is now 10 years since Norstedts published Män som hatar kvinnor, or Men Who Hate Women, which in English was called The Girl with the Dragon Tattoo. MacLehose picked up the trilogy, completed with The Girl Who Played With Fire and The Girl Who Kicked the Hornet’s Nest, for English publication after it was rejected by eight other publishers in the UK.

The three novels, tracing the violent adventures of Salander, a punk computer hacker, and the journalist Mikael Blomkvist, have now sold more than 75m copies worldwide, and more than 14m in the British market.

Lagercrantz has been given “a completely free rein” by Larsson’s estate to continue their stories, said MacLehose. “The reader of this fourth book will know exactly where they are. It will be like coming home, getting back into a hot bath you wished you hadn’t left on a winter’s day – here we are, thrilled to be chained once more to the same calibre of narrator. Lagercrantz is very, very clever.”

Larsson, said MacLehose, “wrote down the shadowy outline of 10 books” in the Millennium series before he died suddenly at the age of 50 in 2004, and before his novels became a worldwide phenomenon. “I haven’t seen it, and I haven’t met anybody who has read it, but he knew he was going to go on,” said MacLehose. “I have the strongest sense that if he was unable to give his creations Salander and Blomkvist fresh life, I think he would have wanted above everything for them to be let loose on the stage.”

The book is being published at the instigation of Larsson’s father and brother, who have said they wanted to “keep alive the characters and world” that Larsson created. “We see it as a way of offering his many readers the continuation they have been longing for. We chose David Lagercrantz because we think he is highly suited to the task. David is a skilled writer who has portrayed odd characters and complex geniuses throughout his career. He will be doing it his own way,” Joakim and Erland Larsson have said in a statement.

The journalist’s partner of 32 years, Eva Gabrielsson, however, has been outspoken about her opposition to the series’ continuation. Because the two never married, and because Larsson died intestate, his estate was divided between his father and brother. Gabrielsson has previously said that Larsson had written 200 pages of a fourth book in the series, but that it would never be published while she holds the draft pages.

She slammed the idea of Lagercrantz’s follow-up in an interview with AFP in Stockholm earlier this month. “I wouldn’t have continued Stieg’s work. It was his language, his unique narrative,” she told the agency. “The worst thing is how saddened Stieg would have been. He never let anyone work on his literary texts. He would have been furious. Who knows, maybe he’ll send a lightning bolt at the book launch.”

But MacLehose is adamant that Lagercrantz is the right person to continue the series. The author of the ghostwritten autobiography of Zlatan Ibrahimovic, I Am Zlatan, he also covered crime for Swedish daily Expressen. “He’s uniquely qualified,” he said. “He knows what he’s talking about, about the police or the intelligence units in the Swedish government, how they work … [And] he’s a writer of tremendous gifts.”

Lagercrantz, who lives on Södermalm in Stockholm, near to where much of the action in the Millennium series is set, has spoken, via a statement from Quercus, of the importance of Larsson’s legacy. “Stieg Larsson was a master at creating complex stories with a lot of different plotlines and that was something I was determined to live up to,” he has said. “[His writing style] is down to earth and unaffected. But there is a kind of journalistic authoritativeness about his work. I realised early on how idiotic it would be for me just to imitate him. This is my own prose.”